EP1658443A1

EP1658443A1 - Actuator

Info

Publication number: EP1658443A1
Application number: EP04738151A
Authority: EP
Inventors: Peter A. MÜLLER
Original assignee: Supraventures AG
Current assignee: Supraventures AG
Priority date: 2003-08-19
Filing date: 2004-08-18
Publication date: 2006-05-24
Also published as: US20060207421A1; WO2005017366A1

Abstract

The invention relates to an actuator (1) in which a fluid can axially move a piston (2) and a piston rod (3). The invention is characterised in that the actuator is provided with means (5, 7) for converting the axial motion of the piston (2) and the piston rod (3) into rotational motion.

Description

fluid cylinder

Technical field

The invention is based on a fluid cylinder according to the preamble of the first claim.

State of the art

Hydraulic and pneumatic cylinders are used today in a large number of machines and devices as power amplifiers and or actuators for pushing, pulling, lifting, turning or holding. In various applications, further demands are placed on the hydraulic and pneumatic cylinders, such as precise positioning of the piston, variable piston speeds, but also safe holding of the piston in a certain position. The position information of the piston is mostly provided by capacitive or inductive sensors which are located on the cylinder housing, the information transmitter being located directly in the piston or piston rod. The measurement is usually linear, i.e. via the stroke of the piston or the piston rod. The piston speed is controlled on the one hand - at a given pressure - via the fluid bores as well as by valves. A servo valve paired with a piston position measurement allows practically every conceivable variation in piston speed over the entire stroke of the piston. Simpler systems

BESTATIGUNGSKOPIE are satisfied, for example for cushioning the end position, of a stepped piston in order to cushion it against a hard impact at the stop.

Furthermore, there are cylinders on the market that must hold a piston position securely, even if the hydraulic or pneumatic line fails. Various systems are known which hold the piston rod securely in the event of a pressure drop, e.g. Check valves that respond when the fluid speed is too high, or external locks, such as clinker locks, that hold onto the object to be held, e.g. described in US 4,529,215, or additional cylinder, which a pure locking resp. Perform unlocking function such as described in US 2003/0140778 A1.

Presentation of the invention

The object of the invention is to provide a simple and inexpensive means for a fluid cylinder of the type mentioned at the beginning, by means of which the various requirements for a fluid cylinder can be met.

According to the invention, this is achieved by the features of the first claim.

The essence of the invention is therefore that means are arranged on the fluid cylinder before the axial displacement of the piston and the piston rod convert into a rotary movement.

The advantages of the invention can be seen, inter alia, in the fact that the fluid cylinders according to the invention can be constructed inexpensively and compactly. By converting the axial movement of the piston into a rotary movement, this rotary movement can be used to perform a wide variety of functions. This radial rotation allows additional requirements for a fluid cylinder can be met as just one stroke in and out as with conventional fluid cylinders. In particular, the piston stroke can be blocked in at least one stroke direction and / or the fluid passage into the interior of the fluid cylinder can be controlled and / or the position of the piston can be measured and / or limited and / or at least one additional unit can be connected.

It is particularly expedient if a spindle, which is located in the rod bore of the piston, is used to convert the axial movement into a rotary movement. By the axial displacement of the non-rotating piston rod, respectively. Piston, the spindle axially supported in the cylinder housing is rotated.

Further advantageous embodiments of the invention result from the subclaims.

Brief description of the drawing

Exemplary embodiments of the invention are explained in more detail below with reference to the drawings. Identical elements are provided with the same reference symbols in the various figures.

Show it:

Fig. 1 is a side view of the fluid cylinder according to the invention with the possibility of flange mounting sensors and stroke limiters FIG. 2 shows a rear view of the fluid cylinder from FIG. 1 with sensors and stroke limitation position

3 shows a side view of a further fluid cylinder according to the invention with an integrated throttle valve controlled by a camshaft

Fig. 4 is a side view of another fluid cylinder according to the invention with an integrated throttle valve axially controlled via a thread

Fig. 5 is a side view of another fluid cylinder according to the invention with an integrated secondary drive design, respectively. synchronization means

Fig. 6 is a side view of a further fluid cylinder according to the invention with an integrated locking mechanism and with a key lock

Fig. 7 cross-sectional view through section AA of the fluid cylinder of Fig. 6 with the view of the mechanical locking by an insert.

Only the elements essential for the immediate understanding of the invention are shown.

Way of carrying out the invention

1 and 2 show a fluid cylinder 1 which can be operated hydraulically or pneumatically and in which a piston 2 and a rotating secured piston rod 3, the latter having a thread 4a in the rod bore 4, into which a non-self-locking spindle 5 is inserted.

The cylinder base 6 has a bore 6a through which the spindle 5 is passed, and at the end of which a turntable 7 is firmly connected to the spindle 5. This turntable 7 is mounted axially (not shown) so that the spindle cannot move axially. When the piston 2 is displaced, at most over the stroke X-X ', by introducing fluid through openings 20a into one of the two cylinder chambers 8 under pressure, the turntable 7 is driven radially. This rotation takes place through the longitudinal movement of the piston rod 3, which cannot rotate due to the anti-rotation device. Due to the internal thread 4 a, the spindle 5 is now set in rotation, and since the spindle cannot be moved axially, the turntable 7 connected to the spindle rotates.

This rotation can now be used for various tasks related to a fluid cylinder.

An angle sensor 9 can be flanged on, which fulfills the same function as a linear position sensor, except that it is compact at the end of the cylinder and that the measuring cable 12 can be led out directly at the end of the cylinder. Additional elements can be integrated, such as one or more switches, e.g. a proximity switch 10 which is activated by an informant 11, e.g. a magnet, call up a function as soon as the magnet and sensor face each other.

The turntable 7 can also have a cam 13, which can move through a radial recess on the cylinder bottom and by radial stoppers 14 or. appropriate shape of the recess, the cam is forced to hold. As a result, the turntable 7 with the spindle 5 can no longer turn and the piston 2 is stopped. By moving the Stopper 14 can thereby set the stroke of the piston 2. The mechanics and the sensors can be protected by a cover 15.

Fig. 3 shows the turntable 7, which has a cam 13 and is used for valve control. In a desired angular position of the turntable 7, i.e. ultimately in the desired piston position, a fluid flow valve (throttle) 17 is activated by the cam 13 via a valve tappet 16. The valve lifter 16 lifts e.g. against a valve spring 18 a valve ball 19 in a flow tube 20 and closes it as soon as the cam 13 has reached its maximum upper pivot point. This stops the piston 2. To start piston 2 again, e.g. To move in the opposite direction, a second bore 21 is required to ensure the cylinder filling. This bore 21 is equipped with a check valve 22 in order to ensure that only fluid always flows into the cylinder through this line part, but none flows out, because the discharge of the fluid is controlled via the cam-controlled valve.

The turntable 7 can also be designed as a cam disk, so that recurring, variable lifting speeds can be achieved over the entire stroke of the piston, due to the partial closure of the flow tube 20 in connection with the valve spring 18 by valve ball 19.

4 shows a further possible valve control. The turntable 7 can be used to drive a toothed shaft or belt drive of a second shaft, a valve shaft 23, which has a thread 24, which leads to an axial displacement of the shaft 23, guaranteed by a longitudinal toothing or keyway 23 a. A gear train 26 enables a corresponding reduction for the valve control and at the same time a connection between the turntable 7 and the valve shaft 23. Appropriate valves 25, such as, for example, plug valves, are seated on the valve shaft 23. The axial displacement serves for the intake or exhaust valve control of the cylinder charge 8. The advantage of this technical design is that the axial displacement of the valve shaft 23, the fluid inlet and at the same time the fluid outlet can be controlled via the stroke. This allows you to approach a prescribed stopping point in very fine doses and just as gently drive away again, without complex servo control.

As already shown in FIG. 3, the valve control explained there also applies to this variant when the valve 25 is closed. Thus, here too, when the valve 25 is closed, the second bore 21, which also has a check valve 22, is activated.

The turntable can also be used for very sensitive measurement with a reduction gear (not shown) or - as will be explained below - can also be used for locking the piston with reduced holding forces.

Fig. 5 shows the turntable 7 as a means for mechanical synchronization of one or more hydraulic cylinders, in which these can be connected to other units with a toothing via a further gear train 26 or shaft 27.

For simple functions, the turntable 7 can also be used for executing separate activities, i.e. can be used as a direct drive. This enables e.g. in a transfer station system, the cylinder for dumping, i.e. use the emptying of a good as usual and at the same time use the function of the turntable 7 of the cylinder 1 in order to mechanically activate a flap so that the good to be emptied is distributed over an area in proportion to the emptying process.

Fig. 6 illustrates the turntable 7 as a locking system. As already mentioned at the beginning, the axially fixed spindle 5 is driven by the piston rod stroke X - X '. By blocking the spindle rotation the piston rod 3 is blocked in the stroke displacement. If the turntable 7 connected to the spindle 5 is now held non-positively, the piston rod 3 is mechanically locked in its position.

The lock can be realized with this invention in different designs, but always compact and simple.

On the one hand, behind the turntable 7, which e.g. on one side has a clinker locking pattern 28, a locking piston 29 with an anti-twist device 30, which has an opposing locking pattern 31. This locking piston 29 is e.g. pressed against the turntable 7 by a spring 32 and locks the piston rods 3 in at least one direction. If the piston 2 is ejected, the clinker lock 28, 31 will allow a rotation of the turntable 7 similar to a ratchet due to its design, the spindle 5 rotates and the piston rod 3 can be moved axially in this specific direction. If a load is now directed against the piston 2 and the fluid pressure is no longer sufficient to carry the load, the clinker lock 28, 31 locks the rotation of the turntable 7 in the opposite direction, the spindle 5 cannot be rotated and the piston 2 cannot move. The cylinder is locked.

For a bilateral locking of the piston rod 3, a variant can be selected in which the turntable 7 and the locking piston 29 interlock positively, e.g. a gearing. A clutch is also conceivable, where both surfaces frictionally and with the appropriate surface pressure prevent the turntable 7 from spinning, respectively. this is taken into account via a suitable reduction ratio as already mentioned above.

The locking piston is normally unlocked using the same fluid as for moving the piston 2. By supplying fluid pressure to one of the cylinder chambers 8 for adjusting the piston, the chamber 8a for the locking piston is also filled at the same time. As a result, the locking piston 29 is pressed backwards against the spring 32 and thus unlocks the turntable 7 and. Spindle 5. By skillful valve control, the piston 2 can first be held in its position by means of the fluid pressure, then it is unlocked and only then does the corresponding fluid pressure and fluid volume move the piston. The control of the locking piston 29 can of course also be accomplished by electrical or manual means.

The holding of the spindle 5 can also be actively supported by introducing a torque onto the turntable 7 so that the spindle 5 is braced against the piston rod 3. In Fig. 5, an output. Synchronization variant shown which can now be used in the opposite direction to the application of force on the turntable 7 and thus on the spindle 5.

Fig. 7 shows a fluid cylinder to be secured, which e.g. outdoors and unsupervised, or must be protected against manipulation, e.g. at e.g. heavy construction machine parts or lifting platforms. With a simple insert 33 between the locking piston 29 and the cylinder cover 15, the axial displacement of the locking piston 29 is prevented and the cylinder as a whole is locked. The insert part 33 can be a tab of a part that can only be extended by means of a safety lock 34.

Of course, the invention is not limited to the exemplary embodiment shown and described.

In these versions, only axial locking pistons 29 were mentioned; these can also achieve the same effect by suitable radial variants in connection with the rotating part 7. LIST OF REFERENCE NUMBERS

Fluid cylinder piston piston rod rod bore spindle cylinder bottom bore turntable cylinder chamberna lock piston cylinder chamber angle sensor0 proximity switch1 informants2 measuring cable3 cams3a recess4 stopper5 cover6 valve tappet7 fluid flow valve8 valve spring9 valve ball0 flow tube0a openings1 bore2 check valve3 valve shaft3a keyway thread valves

train

wave

Clinker closure pattern

blocking piston

twist

closure pattern

feather

insert

Security lock clinker lock

Claims

claims

1. Fluid cylinder (1) comprising a piston (2) and a piston rod (3), the piston and the piston rod interacting and being able to be axially displaced by means of a fluid, the piston (2) and the piston rod (3), characterized in that that means (5, 7) are arranged on the fluid cylinder (1) which convert the axial displacement of the piston (2) and the piston rod (3) into a rotary movement.

2. Fluid cylinder (1) according to claim 1, characterized in that the means for converting the axial movement of the piston (2) into a rotary movement are a spindle (5) and a rotatable means (7) connected to the spindle.

3. Fluid cylinder (1) according to claim 2, characterized in that the spindle (5) is arranged in a rod bore (4) of the piston rod (3), that the spindle (5) is mounted axially in the cylinder housing (6), and that when the piston (2) is axially displaced, the spindle (5) can be set in rotation.

4. Fluid cylinder (1) according to one of the preceding claims, characterized in that by means of the means (5, 7) at least in one stroke direction, the piston stroke is blocked and / or the fluid passage into the interior of the fluid cylinder is controllable and / or the position of the Piston (2) measurable and / or is limited and / or at least one additional unit can be connected.

5. Fluid cylinder (1) according to claim 4, characterized in that the means (7) for the stroke lock has a clinker shape (28) or a positive surface or a frictional surface, each against a spring-loaded and or hydraulic piston (29) axially or is radially lockable.

6. Fluid cylinder (1) according to claim 4, characterized in that the means (7) for controlling the fluid passage into the interior of the fluid cylinder has a cam-like shape (13) or a second shaft (23).

7. Fluid cylinder (1) according to claim 4, characterized in that the means (5, 7) for measuring the position of the piston (2) has sensors (9, 10, 11).

8. Fluid cylinder (1) according to claim 4, characterized in that the means (7) for connecting an additional unit has a gear train (26) with at least one shaft (27).

9. Fluid cylinder (1) according to one of the preceding claims, characterized in that the rotatable means (5, 7) and thus the piston (2) can be blocked by means of an element (33, 34) which can be activated from outside the fluid cylinder.